I don't know if you only reference the dll's in your project, but if so I think it would be easier for you to solve your problems if you checked out the code as used that instead.
I'm actually getting this same error on playback for all sites... there must be something messed up in my MP config... I just upgraded to MP 1.11.0. Let me get that sorted out first.
I can playback other video, but OV cannot play anything:
[04-03 10:27:36,099] [MPMain ] [WARN ] Error adding 'MediaPortal Url Source Splitter' filter to graph: Exception from HRESULT: 0xFFFFFFFB
Turns out my install was corrupt somehow and the OV could not find the MP URL Source Splitter... did a complete clean install of MP and now the hockeystreams plugin works in OV2.0.
I'll do a bit more testing, then upload the plugin.
The issue with the site showing up seems to be solved but now I am getting an exception for a malformed url...
[04-04 09:35:56,536] [OnlineVideos] [WARN ] System.FormatException: Input string was not in a correct format.
I have tried both live streams last night and archived this morning with and without a location entry. The attached example is for archived game with location.
Just tried an archive game from this afternoon and it appears you solved it. I will try a live stream later but it sounds like the solution wasn't tied tied to the live vs. archive workflow.